I believe G4DGU did some work on this some years ago. I don't know if he has an Internet address - G3SEK might know. 73 Peter G3RZP -- FAQ on WWW: http://www.contesting.com/ampfaq.html Submissions: amps@contesting.com Administrative requests: amps-REQUEST@contesting.com Problems: owner-amps@contesting.com Search: http://www.contesting.com/km9p/search.htm